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Testing for Early Diagnosis of Alzheimer’s Disease - Episode 2

Common Screening Tools for AD and Their Importance

Dr Atri lists the common screening tools used to form an AD diagnosis.

Alireza Atri, MD, PhD: It’s important to go through a process when an individual shows up with a concern or you as a clinician have a concern or you get a report from somebody who knows the patient well. Part of the process is to use an objective measure; people sometimes call them screening tools. In this case, if someone has a concern, we’re case finding and trying to take a subjective complaint or a concern or change and show some objective changes that we can show a level of performance that’s lower than it should be.

One of the first steps after the history is to do 1 of the validated brief cognitive assessments. There are several to choose from. For example, the Montreal Cognitive Assessment, the MoCA, is freely available, and there’s a certification process that people can go to. That’s very useful but not always necessary. That’s a good screen. It’s out of 30 and has a number of different components, including attention, visuospatial function, executive components, language components, and memory components and orientation. It’s quite sensitive to early changes. The Mini-Mental State Examination, the MMSE, has also been used. The GPCOG [General Practitioner Assessment of Cognition] is another one that’s used, but not as much in the United States. There’s also the Blessed Dementia Scale. The Information-Memory-Concentration scale is another. These are all validated scales.

Some people like to do things like Mini-Cogs, which are brief instruments, like learning 3 words, doing a clock-drawing test, and then recalling those words. It’s important to know that each has pros and cons, including duration, how long it takes to give, and how sensitive they are to different stages of performance. But 1 thing I always say is to treat not the number on these instruments but the patients in front of you. There’s no 1 number that gives you a diagnosis.

These things are very much impacted by level of education or cultural and other factors, so it’s possible to get a score that’s higher than a cutoff—even 29 of 30 on a Mini-Mental State Examination—and still have true clinical deterioration and problems, which may show up on harder tests or neuro kinds of testing or neuropsychological testing. But in primary practice, specialty practice, and even subspecialty practice, a validated brief cognitive assessment is important to do for detection, knowing the next steps, and sometimes the opportunity to follow the patient in how they’re progressing.

These validated brief cognitive assessments are an important part for detection. They can certainly inform the diagnosis of clinical stage, although stage isn’t based only on cognitive performance. One has to consider things like daily function and behavior for staging of the clinical aspect, whether it’s mild cognitive impairment or dementia stage, and whether it’s mild, moderate, or severe. It’s important for detection. In some cases, based on where the domains are being affected, they could even tell you if they’re also congruent, with subjective complaints about what could potentially be the underlying etiology of causes. Some patterns of performance map on better to having increased likelihood that the neuropathological changes are due to Alzheimer disease. There’s no 1:1 correspondence, though.

There’s the part that comes with detection and then a part for longitudinal tracking. That’s always important in busy practices to take a stage-appropriate cognitive assessment and be able to follow it along. This is important in our management paradigm because with some of these tests, there are some expectations about change over time. Generally, at all stages in Alzheimer disease, when you look at patients and placebo groups, which do better in many ways than patients in the real world, there’s often decline over even 6 months.

With the number of points of decline on these instruments—some of them are published—there’s a general understanding of where very fast or very slow progresses are. It’s important for monitoring any intervention, and with not just drugs but other interventions, such as behavior. That’s something I frequently do when I see patients. I have them back every 3, 4, or 6 months depending on the stage and what’s going on. Sometimes when we induce some therapy or medication, you can see changes that correlate with this, so that’s important. For long-term management, it’s also important, at least for prognosis, because when individuals are declining faster, one needs to pay attention, and the prognosis may be different.

This transcript has been edited for clarity.